Electronically tunable distributed feedback lasers.

The fabrication and performance characteristics of frequency tunable two-section distributed feedback lasers are reported. The lasers are of the double channel planar buried heterostructure type and utilize a second order grating for frequency selective feedback. The laser emits in a single frequency with a CW linewidth of ~50 MHz. The single frequency output can be tuned by ~2 angstroms by varying the current through one of the two sections. Electronically tunable sources of this type are potentially useful for coherent fiber transmission systems.